[dlmodule][utest] add QEMU regression coverage

.github/utest/configs/components/dlmodule.cfg

@@ -0,0 +1,9 @@
+# Real ARM ELF fixtures, loaded through the filesystem and dlopen().
+CONFIG_RT_CONSOLEBUF_SIZE=1024
+CONFIG_RT_NAME_MAX=24
+CONFIG_RT_USING_CI_ACTION=y
+CONFIG_RT_USING_MODULE=y
+CONFIG_RT_USING_DFS=y
+CONFIG_RT_USING_POSIX_FS=y
+CONFIG_RT_UTEST_DLMODULE=y
+CONFIG_UTEST_THR_STACK_SIZE=8192

.github/workflows/utest_auto_run.yml

@@ -152,6 +152,8 @@ jobs:
             config_file: "components/dfs.cfg"
           - platform: { UTEST: "A9",            RTT_BSP: "bsp/qemu-vexpress-a9",      QEMU_ARCH: "arm",     QEMU_MACHINE: "vexpress-a9", SD_FILE: "sd.bin", KERNEL: "standard", "SMP_RUN":"" }
             config_file: "components/libc.cfg"
+          - platform: { UTEST: "A9",            RTT_BSP: "bsp/qemu-vexpress-a9",      QEMU_ARCH: "arm",     QEMU_MACHINE: "vexpress-a9", SD_FILE: "sd.bin", KERNEL: "standard", "SMP_RUN":"" }
+            config_file: "components/dlmodule.cfg"
 
     env:
       TEST_QEMU_ARCH: ${{ matrix.platform.QEMU_ARCH }}
@@ -300,6 +302,10 @@ jobs:
           fi
 
           scons --pyconfig-silent -C $TEST_BSP_ROOT
+          if [[ "$TEST_CONFIG_FILE" == "components/dlmodule.cfg" ]]; then
+            grep -q '^#define RT_UTEST_DLMODULE' $TEST_BSP_ROOT/rtconfig.h
+            python3 tools/ci/test_run_dlmodule_qemu.py
+          fi
           scons -j$(nproc) --strict -C $TEST_BSP_ROOT
 
       - name: QEMU Run Test
@@ -312,7 +318,10 @@ jobs:
             mkfs.fat $TEST_BSP_ROOT/sd.bin
           fi
 
-          if [[ "${{ matrix.platform.QEMU_ARCH }}"  == "aarch64" ]]; then 
+          if [[ "$TEST_CONFIG_FILE" == "components/dlmodule.cfg" ]]; then
+            python3 tools/ci/run_dlmodule_qemu.py --kernel $TEST_BSP_ROOT/rtthread.bin \
+              --disk $TEST_BSP_ROOT/sd.bin --log qemu_output_$TEST_QEMU_ARCH.log
+          elif [[ "${{ matrix.platform.QEMU_ARCH }}"  == "aarch64" ]]; then
             sudo apt-get -yqq install device-tree-compiler
             if [[ "${{ matrix.platform.QEMU_MACHINE }}"  == "virt" ]]; then
               qemu-system-$TEST_QEMU_ARCH -M virt -cpu max -smp 4 -m 128M -kernel $TEST_BSP_ROOT/rtthread.bin -nographic \
@@ -406,9 +415,11 @@ jobs:
                 > qemu_output_$TEST_QEMU_ARCH.log  2>&1 &
           fi 
 
-          QEMU_PID=$!
-          disown $QEMU_PID
-
+          if [[ "$TEST_CONFIG_FILE" != "components/dlmodule.cfg" ]]; then
+            QEMU_PID=$!
+            disown $QEMU_PID
+          fi
+
       - name: Monitor qemu log
         if: ${{ env.TOOLCHAIN_INSTALLED != '' && success() }}
         # Same known-flaky qemu-virt64-riscv standard kernel utest run as the previous step.

components/libc/posix/libdl/SConscript

@@ -8,5 +8,7 @@ CPPPATH = [cwd]
 
 if rtconfig.PLATFORM in ['gcc']:
     group = DefineGroup('Libc', src, depend = ['RT_USING_MODULE'], CPPPATH = CPPPATH)
+    if GetDepend('RT_UTEST_DLMODULE'):
+        group += SConscript('utest/SConscript')
 
 Return('group')

components/libc/posix/libdl/utest/Kconfig

@@ -0,0 +1,10 @@
+config RT_UTEST_DLMODULE
+    bool "dlmodule ELF loading and relocation tests (32-bit ARM GCC)"
+    depends on ARCH_ARM_CORTEX_A && !ARCH_CPU_64BIT && !RT_USING_SMART
+    depends on RT_USING_MODULE && RT_USING_DFS && RT_USING_POSIX_FS
+    default n
+    help
+        Build real 32-bit ARM ELF modules and test dlopen, dlsym and dlclose.
+        Requires GCC and a writable filesystem mounted at /.
+        Fixture generation uses -marm -mcpu=arm926ej-s and verifies the
+        GCC-generated ELF layout, section types and symbol properties.

components/libc/posix/libdl/utest/SConscript

@@ -0,0 +1,23 @@
+import os
+import subprocess
+import sys
+from building import *
+
+Import('env')
+
+cwd = GetCurrentDir()
+variant = Dir('.').abspath
+fixture_sources = Glob('fixtures/*.c') + Glob('fixtures/*.ld')
+builder = os.path.join(cwd, 'build_fixtures.py')
+
+def build_fixtures(target, source, env):
+    subprocess.check_call([sys.executable, builder, '--cc', env.subst('$CC'),
+                           '--output', str(target[0])], env=env['ENV'])
+
+header = env.Command('dlmodule_fixtures.h', [builder] + fixture_sources,
+                     Action(build_fixtures, 'Building dlmodule ELF fixtures'))
+group = DefineGroup('dlmodule-utest', ['dlmodule_tc.c'],
+                    depend=['RT_UTEST_DLMODULE'], CPPPATH=[cwd, variant])
+env.Depends(group, header)
+
+Return('group')

components/libc/posix/libdl/utest/build_fixtures.py

@@ -0,0 +1,108 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: Apache-2.0
+"""Build ARM test modules from source; never commit generated ELF/header files."""
+import argparse
+from pathlib import Path
+import shlex
+import struct
+import subprocess
+
+
+def verify_fixture(name, data):
+    """Check the ELF shape so a compiler change cannot silently remove a test."""
+    if data[:6] != b'\x7fELF\x01\x01':
+        raise RuntimeError(name + ': expected little-endian ELF32')
+    kind, machine = struct.unpack_from('<HH', data, 16)
+    if machine != 40 or kind != (3 if name in ('dg_dyn', 'dg_imp') else 1):
+        raise RuntimeError(name + ': incorrect ARM ELF type')
+    offset = struct.unpack_from('<I', data, 32)[0]
+    stride, count, strings = struct.unpack_from('<HHH', data, 46)
+    sections = [struct.unpack_from('<10I', data, offset + i * stride) for i in range(count)]
+    names = data[sections[strings][4]:sections[strings][4] + sections[strings][5]]
+    section_names = [names[s[0]:].split(b'\0', 1)[0].decode() for s in sections]
+    symbols = {}
+    for section in sections:
+        if section[1] != 2:
+            continue
+        strings = sections[section[6]]
+        table = data[strings[4]:strings[4] + strings[5]]
+        for pos in range(section[4], section[4] + section[5], 16):
+            symbol = struct.unpack_from('<IIIBBH', data, pos)
+            label = table[symbol[0]:].split(b'\0', 1)[0].decode()
+            if label:
+                symbols[label] = symbol
+    if name == 'dg_rel':
+        assert symbols['common_value'][5] == 0xfff2
+        assert symbols['aligned_value'][5] == 0xfff2 and symbols['aligned_value'][1] == 16
+    elif name == 'dc_ptr':
+        assert symbols['common_value'][5] == 0xfff2
+        assert any(s[1] == 9 and section_names[s[7]] == '.data' and s[5] > 0 for s in sections)
+    elif name == 'db_multi':
+        assert section_names[symbols['bss_value'][5]] == '.bss'
+        assert section_names[symbols['common_value'][5]] == '.common'
+        assert sections[symbols['bss_value'][5]][1] == 8
+        assert sections[symbols['common_value'][5]][1] == 8
+    elif name == 'dn_addr':
+        assert sections[symbols['probe'][5]][3] == 0x1000 and symbols['probe'][1] == 0
+        assert sections[symbols['initialized'][5]][3] == 0x2000
+    elif name == 'dd_dbg':
+        assert any(s[1] == 9 and section_names[s[7]].startswith('.debug') for s in sections)
+    elif name == 'dt_text':
+        assert symbols['first'][5] != symbols['second'][5]
+        assert symbols['first'][1] == symbols['second'][1] == 0
+    elif name in ('du_sym', 'dz_none'):
+        assert symbols['external_func'][5] == 0 and symbols['external_func'][3] == 0x12
+        if name == 'dz_none':
+            assert not any(s[3] == 0x12 and s[5] != 0 for s in symbols.values())
+    elif name == 'dg_imp':
+        # Dynamic symbols are in .dynsym; inspect the string table as well.
+        assert b'rt_kprintf\0' in data
+
+
+def build(cc, output):
+    sources = Path(__file__).resolve().parent / 'fixtures'
+    directory = output.parent / 'dlmodule-fixtures'
+    directory.mkdir(parents=True, exist_ok=True)
+    # ARMv5 literal-pool relocations are supported by libdl/arch/arm.c.
+    # Cortex-A9 also executes these instructions; avoid unsupported MOVW/MOVT relocations.
+    flags = ['-marm', '-mcpu=arm926ej-s', '-O0', '-fcommon', '-fno-pic',
+             '-fno-stack-protector', '-fno-unwind-tables', '-fno-asynchronous-unwind-tables']
+    modules = [
+        ('dg_rel', 'globals', [], []),
+        ('dg_dyn', 'globals', ['-fPIC', '-mlong-calls', '-DDYNAMIC_FIXTURE'], ['-shared']),
+        ('dg_imp', 'globals', ['-fPIC', '-mlong-calls', '-DDYNAMIC_FIXTURE', '-DKERNEL_IMPORT'], ['-shared']),
+        ('dc_ptr', 'common_target', [], []),
+        ('db_multi', 'multi_bss', [], ['-Wl,-d,-T,' + str(sources / 'multi_bss.ld')]),
+        ('dn_addr', 'sections', [], ['-Wl,-T,' + str(sources / 'nonzero.ld')]),
+        ('dd_dbg', 'sections', ['-g'], []),
+        ('dt_text', 'multi_text', [], []),
+        ('du_sym', 'undefined', [], []),
+        ('dz_none', 'undefined', ['-DZERO_EXPORTS'], []),
+    ]
+    lines = ['/* Generated ELF fixtures; do not edit. */',
+             'struct dlmodule_fixture { const char *name; const unsigned char *data; unsigned size; };']
+    for name, source, extra, link in modules:
+        obj = directory / (name + '.o')
+        elf = directory / (name + '.mo')
+        subprocess.run(cc + flags + extra + ['-c', str(sources / (source + '.c')), '-o', str(obj)], check=True)
+        mode = [] if '-shared' in link else ['-r']
+        subprocess.run(cc + ['-nostdlib'] + mode + link + [str(obj), '-o', str(elf)], check=True)
+        data = elf.read_bytes()
+        verify_fixture(name, data)
+        lines.append('static const unsigned char ' + name + '[] = {')
+        for offset in range(0, len(data), 16):
+            lines.append('    ' + ', '.join('0x%02x' % byte for byte in data[offset:offset + 16]) + ',')
+        lines.append('};')
+    lines.append('static const struct dlmodule_fixture dlmodule_fixtures[] = {')
+    for name, _, _, _ in modules:
+        lines.append('    {"%s.mo", %s, sizeof(%s)},' % (name, name, name))
+    lines.append('};')
+    output.write_text('\n'.join(lines) + '\n')
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--cc', required=True)
+    parser.add_argument('--output', type=Path, required=True)
+    args = parser.parse_args()
+    build(shlex.split(args.cc), args.output.resolve())